Rinse the breast pump in warm water till all detergent has completely been removed. Preferably air dry all parts of pump on a clean towel or on a designated spot on the dish rack.
As for sterilizing the top best breast pump, it may be done after every feed, but this will be dependent on manufacturer instructions. Not all machines require this after every feed. Once a day is more than enough. If you are going to sterilize the pump, you may do so with a special sterilizer machine, on the top rack of your dishwashing machine or even in boiling water.
For pumps that make use of tubes to collect milk in a container attached at the end, make sure that you clean the tubes thoroughly and run warm water through it. Make sure that you detach the tubes from the machine before you clean it.
Before you handle the breast pump again, make sure that you wash your own hands with soap and water. This will prevent any contamination of the pump with germs. If you would like to know more, read our breast pump reviews.